Revivifying of spent decolorizing materials



Patented July 24, 1928.

UNITED STATESPATENT OFFICE;

OSCAR L. BARNEBEY, OF coLumnus, OHIO. BEVIVI'FYING OF SPENT DECOLOBIZING MATERIALS. No Drawing. Application filed Apr11 12, 1924, Serial No. 706,100. Renewed March 15, 1928.

This invention relates to materials serving the soda process in the ordinary soda pulp 55 as refining agents or decolorizers 1n the mill. Not only do I find that the same treatment of liquids and to methods of reefi'ect can be accomplished with fibre of this fining or decolorizing the liquids. I type, but indeed a much superior filtration 5 Among the objects of this invention to can be obtained.

provide a composition for refining or de- Further, I have found that the used car- 80 colorizing liquids, preferably organic liqbon-paper pulp mixture can be reconverted uids such as sugar solutions and syrups, into valuable decolorizing carbon practically vegetable oils, pharmaceuticals, chemicals, free from inert material and very valuable n mineral oils and the like, which decolorizing for refining of sugar and other substances composition may be readily recovered and. as well, as will appear from my process hercrevivified for further use after it has become in described. spent or exhausted in the process. In carrying out my process, the paper A further object of this invention is to pulp or similar cellulose fibre material is 15 provide a process for treating liquids of the preferably mixed with the sugar liquor, "egcharacter heretofore described by means of ctable oil, glycerine or other material being these decolorizing and refining agents. refined. The paper is stirred thoroughly A still further object of this invention is with the liquor or other substances, thus to provide a process for treating the spent contacting the entire mass with the fibres 20 or exhausted decolorizing material after it of the paper and at the same time thorhas been used in one or more treatments of oughly breaking up the fibres to give good 7 the liquids and to regenerate or revivify the admixture with solutions being refined. refining and decolorizing properties pos- After thorough agitation of the paper pulp sessed by the agent before its use as a dewith sugar liquors or similar liquids being 25 colorizer. refined, high grade finely divided decoloriz- Other, further and more specific objects of ing carbon is added and likewise stirred this invention will become readily apparent thoroughly with the material, thus producto persons skilled in the art from a considing an intimate mixture of decolorizing careration of the following description. bon and paper pulp along with any filter- 3 In refining such materials as sugar and able impurities in suspension with the sugar sugar syrups, vegetable oils, etc., the finely liquor. divided decolorizing carbons-on the market The mixture of paper pulp and carbon is usually require the use of av material like now passed through a filter press which has kieselguhr, sil-o-cel or other silicious mabeen precoated with paper pulp" so that the 35 terials to assist in filtration. When the carleaves of the press are covered with a thin,

bons are used without some assisting mauniform layer of pulp, and after the mix terial of this type the carbons tend to clog ture is in the press the solid press cake is the filters and give other mechanical trouwashed thoroughly to remove any su ar bles. Silicious materials of this type, howtherefrom. After thorough washing ot er 40 ever, have the very serious handicap of dibatches of sugar liquor can be thrown upon luting the carbon and this is objectionable. the same filter press leaves until the press if the carbon is to be revivified and used over cake has been built up to such a thickness again one or more times. This addition of as to make further addition of paper-carbon more silicious material to the used carbon to cake impracticable, at which time the thorfurther aid in filtration lessens the carbon oughly washed cake is removed from the content to a very material extent and the silifilter press and used with subsequent batches cious matter is cumulative, finally requiring of sugar liquor for several times until the the carbon to be discarded altogether, resultcarbon has had its refining power diminished ing in much loss. beyond the state of minimum efiiciency or 50 I have found that the effect accomplished until it is no longer practical to use it furwith kieselguhr. sil-o-cel and other silicious ther.

materials can be produced with cellulose In these subsequent treatments of new fibre material, such as soda pulp made in the batches of sugar liquor it is seldom necessary ordinary process of manufacture of paper by to add but small additional amounts of paper pulp. In fact, frequently none whatever is added. The filter presses, however, are best precoated with paper pulp for each filtration as this prevents the filter clothfrom becoming plugged up with finely divided carbon mixture.

When the carbon has become essentially exhausted or spent and has been thoroughly Washed, the mass is dried. The dried mass is then treated to restore the original decolorizing power of the decolorizing carbon and also to convert the paper pulp into additional decolorizing carbon for future use. To accomplish this, the dried mass is introduced into a rotary furnace which is heated both externally and internally in such a manner as to give a maximum temperature between 700 and 1100 (3., and of this ran e the temperatures between 800 and 900 C. is preferred. The entrance end of the furnace is heated to give an application of approximately 400 to 800 0., the temperature gradually increasing until the zone is reached giving an application of 700 to 1100 C. as final treatment. Upon heating the decolorizing carbon-paper pulp mixture the first effect is to char or carbonize the paper pulp, the paper being decomposed and converted into carbonaceous material. Also the saccharine materials as well as phenols, tannins, etc. subtracted from the sugar liquors are also decomposed by the heat, thus producing additional carbonaceous material. This carbonizing takes placeat temperatures of about redness, that is to say, between 400 and 800 C.

After this carbonizing is completed in the furnace and the temperature rises in the hotter zone of the furnace to 700 to 1100 0., the carbonized material undergoes a second treatment by contact of same with gase ous products of combustion, namely carbon dioxide and water, hereinafter called oxygenated gases. Additional Water in the form of steam or superheated steam is likewise added at times although not always necessary. These products of combustion at the temperatures enumerated, namely 700 to 1100 (3., serve as mild oxidizing agents and react with the carbonized mass and remove any tarry materials produced by. carbonization and further react with the carbon itself to open up the pores of the same, thus proucing a very reactive carbon material.

Air can be used in small limited amounts, and if used in a controlled manner can be caused to oxidize the impurities and revivify the spent carbon as Well as produce decolorizing properties in the charcoal. Care must be exercised in using air, since an excess of air will consume the entire carbon content. The temperatures for using air are upwards from about 300 C.

The decolorizing carbon after treatment is discharged from the furnace into coolers mama? and from the coolers is discharged subseq liently into steel drums. This carbon is t en ready to be used again for refining operations and to this end is again mixed with fresh paper pulp to aid filtration, stirring the paper pulp and carbon materials together with the material being refined, filter pressing, washing, drying, treating, etc., in a cyclic manner, thus using the carbon over and over again, time after time.

If a considerable quantity of filter paper is used it is not necessary to add any further quantities of decolorizing carbon, provided t e process is regulated well and mechanical losses are not too great. In the ordinary case, however, small quantities of the decolorizing carbon are added from time to time.

In following my process the only diluting matters which can contaminate the decolorizing carbon are the inorganic substances which the carbon takes up from the sugar liquor or similar material being refined, and occasionally it is desirable to treat the decolorizing carbonaceous mass with a mineral 'acid to remove such mineral matter. This is done by treating the carbon with hydrochloric acid, sulphuric acid, or phosphoric acid. In this relation, I ordinarily prefer to use hydrochloric acid. After treatment with acid, if residual acid is objectionable or detrimental to the use for which the revivified carbon is to be put, the acid must be thorou hly washed out, previous to use of the car on, otherwise impurities Will be .introduced into the liquid being refined and cause detrimental efi'ects. The carbon is again heated to remove moisture and any re maining volatile acid.

A specific example of carrying out my in vention is as follows: 1000 pounds of 96 test raw sugar is dissolved in water to produce a 60% sugar liquor. The sugar liquor is heated to approximately 180 F. and to the hot liquor is added 5 pounds of paper pulp fibre and 20 pounds of high grade decolorizing carbon. The pulp and carbon are thoroughly stirred with the liquor for about 20 minutes. In the meantime, the filter press leaves are precoated with a layer of paper pulp, about to inch thick. The sugar liquor is then filtered. The residue is removed from the filter press and added to a new batch of sugar liquor. is repeated four or five times without the addition of more paper pulp, except to coat the filter presses, pulp mixture is washed thoroughly, dried, carbonized at temperatures between 400 and 800 (1. followed by treatment with oxy genated gases at temperatures between 800 and 900 0., which operation revivifies the original decolorizing carbon and also manufactures more decolorizing carbon from the paper pulp for future refining operations.

This o eration? after which the carbon- After the sugar is removed from the press, dried, carbonized,

and treated with oxygenated gases as above described, to restore and produce more decolorizing carbon.

\Vhile the example given above is that of refining sugar and sugar liquors the process is not limited to this particular refining operation but on the contrary the process can be used for refining other materials in solution as well as mineral oils, vegetable oils pharmaceuticals, chemicals and the like, the p example being given to illustrate one of the most valuable of the applications of the invention and which is ty ical of the general application and use of t e same.

From the foregoing descriptions it is to be seen that a three fold operation is involved in my process. First of all, I use cellulose fibre materials to aid filtration with decolorizing carbon. Second, I restore the original value of decolorizing carbon, and third, I actually manufacture decolorizing carbon from the cellulose fibre in the process of revivifying the previously used carbon and by virtue of the use of paper pulp for aid in the filtration I manufacture a very high grade decolorizing carbon containing very little diluent material, in fact, only suc diluent material as has been subtracted by tne refining operation itself.

In carrying out the refining operation I prefer to use only high grade decolorizing carbon and cellulose material which by nature of my process is converted into decolorizing carbon, all of which materials are uncontaminated with diluent minerals or other similar material. In consequence of this I accomplisha much better refining operation and further I accomplish the entire operation or refining in an improved manner since the mechanical operation is much easier to manipulate than the usual process of refining using decolorizing carbon along with kieselguhr and other mineral materials of similar nature.

present invention is not limited to the specific details set forth in the foregoin examples which should be construed as 1 lustrative and not by way of limitation, and in view of the numerous modifications which may be effected therein without departing from the spirit and scope of this invention, it is desired that only such limitations be imposed as are indicated in the appended claims.

I claim as my invention:

1. A composition for decolorizing liquids comprising the charred and activated product of a mixture of decolorizing carbon and cellulose fibre.

2. A composition for decolorizing liquids comprising the charred and activated product of a mixture of decolorizing carbon and paper pulp.

3. In a process of revivifying a spent mixture of decolorizing carbon and cellulose fibres which has been used in clarifying liquids, charring the spent mixture and then activating the charred product by heating in the presence of a mild oxidizing agent.

4. In a process of revivifying a spent mixture of decolorizing carbon and cellulose fibers which has been used in clarifying liquids, charring the spent mixture and activating the charred product by heating at temeratures of 7001100 C. in the presence 0 oxygenated gases.

5. In a process of revivifying a spent mixture of decolorizing carbon and cellulose fibers which has been used in clarifying liquids, charring the spent mixture and activating the charred product by heating at temperatures of 7001100 C. in the presence of steam.

6. In a process of revivifying a spent mixture of decolorizing carbon and paper pulp "which has been used in clarifying liquids,

charring the spent mixture and then activating the charred product by heating at a temperature above that required for charring and in the presence of a mild oxidizing agent.

7. In a process of revivifying a spent mixture of decolorizing carbon and cellulose fibres which has been used in clarifying liquids, charring the spent mixture at temperatures of 400-800 C. and then activating the charred product by heating at 7 001100 C. in the presence of a mild oxidizing agent.

8. In a process of revivifying a spent mixture of decolorizing carbon and cellulose fibres which has been used in clarifying liquids, charring the spent mixture and then activating the charred product by heating in the presence of a mild oxidizing agent and then treating the activated material with a mineral acid.

9. In a process of revivifying a spent mixture of decolorizing carbon and cellulose fibres which has been used in clarifying liquids, charring the spent mixture and then activating the charred product by heating in the presence of a mild oxidizing agent, treating the activated material with a mineral gold and then washing the excess acid thererom.

. 10. In a process of revivifying a spent eral acid, washing the excess acid therefrom mixture of decolorizing carbon and cellulose and then removing moisture and traces of fibres which has been used in clarifying liqacid remaining in the activated material by 10 uids, charring the spent mixture and then heating said material.

5 activating the charred product by heating In testimony whereof, I hereunto affix my in the presence of a mild oxidizing agent, signature. treating the activated material with a min- OSCAR L. BARN EBEY. 

